Closure plug and method of forming same



April 30, 1935. R. L. PARISH 2 eets-Sheet' l Filed May 13, 1952 April1935- R. 1.. PARISH R 1,999,205

CLOSURE PLUG AND METHOD OF FORMING SAME Filed May 13, 1952 2Sheets-Sheet 2 m JZ\ J4 ZL9\ I l I Patented Apr. 3i), 11%35 rarer cariesCILQ'PSETRE PLUG AND METHQD @IF FEDRMUING SAME Richard IL. Parish,Chicago, lillL,

assignor to American Flange & Manufacturing (Company, Chicago, lit, acorporation of lillinois Application May 13, 1932, Serial No. 611,067

8 Claims.

My invention relates to closure plugs and method of forming same, and ithas to do more particularly with a plug well adapted for closure of theopenings in metallic containers suited for transportation and storage ofoil, gasoline, and the like.

One of the objects of my invention is to provide an improved, simple,inexpensive and light weight, yet highly efiicient and durable, closureplug formed of sheet metal.

A further object is to provide from a single piece of sheet metal a plughaving an externally threaded, cup-shaped body, an exteriorgasketreceiving and supporting surface, a head with a seal seat thereon,and lug means integral with the body and formed therein in the shapingof the sheet metal for facilitating insertion and removal of the plugfrom the opening which it is adapted to close.

Another object is to provide a novel and inexpensive method of forming aplug of the foregoing character, the same being carried out in such amanner as to condense, thicken and strengthen the wall of the completedplug surficient to accommodate the finishing operations and to withstandthe conditions of use to which it may be subjected.

Other objects and advantages will become apparent as this descriptionprogresses and by reference to the drawings wherein,

Figure 1 is a perspective view of'ablank from which the body of the plugmay be formed;

Fig. 2 is a vertical sectional view of die structure (diagrammaticallyshown) illustrating the initial forming of the blank of Fig. 1 into acup shape;

Fig. 3 is a perspective View of the cup formed by the die of Fig. 2;

Fig. 4 is a vertical sectional view of die structure, illustrating apreliminary forming operation on the cup of Fig. 3; v i

Fig. 5 is a section taken substantially on line S5 of Fig. 4;

Fig. 6 is an elevational view of the cup after its preliminary formingby the die of Fig. 4;

Fig. '7 is a vertical sectional view of a finalforming die, illustratingin vertical section the cup formed thereby;

Fig. 8 is a section taken substantially on line for rotation thereof;and

Fig. 11 is an elevational view, partially in section, of the finishedplug.

In general, the steps involved in making a plug 5 according to myinvention include the forming of a single cylindrical blank of sheetmetal of desired size into a cup-shaped blank of greater depth than thefinished plug. This cup blank is then acted upon by a die suitablyshaped to strike or 10 punch the side wall of the cup radially inward atdiametrically opposed points to initially form opposed hollow lugsprojecting within the cup body; and during this same operation Ipreliminarily compress the side wall of the cup in 15 axial direction,reducing somewhat its height and increasing slightly the thickness ofits side wall. The cup blank thus treated is then subjected to theaction of a final-forming die to further compress its side wall in axialdirection, thereby further compacting and thickening the cup side wallto the desired extent for threading and final finishing of the plug.During this final forming operation, the inwardly projecting lugsinitially pressed from the side wall of the cup are finally shaped toprovide finished lugs which may be engaged by a suitable tool (such as amonkeywrench, screw driver, bar of metal, etc.), inserted within thefinished plug for screwing the same 7 into or out of the opening it isadapted to close. 3

After the cup body has been formed as last stated, it is finallyfinished to form the completed plug by externally threading the same andby shaping the upper exterior part thereof above the threads to providea gasket receiving space and a head having a seal seat surface.

In the drawings. I have illustrated the foregoing steps of my inventiontogether with one form of structure which may be employed in carryingout the same. Specifically, a preformed cylindrical blank i5 (Fig. 1) isformed into a cup l6 (Fig. 3) by die structure which may take the formof male and female die members ll and i8, respectively (Fig. 2) I Thepreformed cup it is'next acted upon by the die structure which may takethe form shown in Fig. 4. Specifically, the cup blank is inserted (withits bottom downward) in a female die member l9 which is provided with apair of internal, diametrically opposed punch members 28 which projectinwardly into the die cavity 2!, which die members 20 have their uppersurfaces, preferably, rounded as at 22. After the cup 56 is inserted inthe die member i9, it is then engaged and pressed inwardly by a male diemember 23. This latter die member is provided with a head portion 24having a reduced portion 25 depending therefrom providing a shoulder 25which engages the upper rim of the cup blank. This die member 23 is alsoprovided in its reduced portion 25 with diametrically opposed recesses2'! adapted to align with the die punch members 29, which re cesses areof enlarged dimensions adapted to freely receive the punch members 23and the cup wall material forced thereinto by such punch members. In theuse of this die structure (Fig.

'4), as the die member 23 is moved inwardly with the cup Hi, thefemalepunch members 23 strike or punch the side wall of the cup into themale die recesses 21 forming preliminary indentations in the side wallof the blank and providing inwardly projecting, hollow anddiametrically-opposed lugs 28, of a shape best shown in Figs. 4 and 6.During this operation, the side wall of the cup is slightly compressedaxially and is slightly thickened thereby reducing the height of thesame as clearly shown in Figs. 4 and 6.

The cup blank i5 is, preferably, finally completed by a die structuresuch as that illustrated in Fig. 7. More particularly, this diestructure includes a female die member 29 having a cylindrical,unobstructed cavity 30, in which the preformed cup blank of Fig. 6 isadapted to be seated. The preformed blank is then acted upon by a maledie member 3| which is provided with a head 32 and a reduced dependingshank portion 33 having diametrically opposed recesses 34 adapted toalign with and receive the preliminarily-formed hollow lugs 28. Withthis structure, as the male die member 3| is moved inwardly, theshoulder 35 thereof formed by its portions 32 and 33 engages the top ofthe blank rim with the lugs 28 received in its recesses 34, and as thismovement is continued the side wall of the cup is compressed axially andcompacted to further and finally thicken the same as shown in Fig. '7.As this action takes place, the metal forming the lugs 28 is bowed andfiowed somewhat further inwardly and the top portions of these lu'gs areflattened so that they finally take the shape shown in Figs. 7 to 10,inclusive. It will be noted that the height of the cup wall has beenreduced so that the top portions of the lugs 28 extend approximatelyfiush with the top edge of the cup, and that the lugs so formed takesubstantially a wedge-shape in horizontal section (Figs. 8 and 10). Itwill be further noted that the finished lugs 28 are so shaped andrelated that an object, such as a bar of metal 36 as illustrated in Fig.10, inserted within the plug body will seat against opposite sides ofopposed lugs at the bases of the lugs so that a firm and secureengagement is insured and great pressure may be applied to the bar 35 torotate the plug body Without danger of distortion and injury to the plugbody and lugs.

After the plug blanks has been finished to the extent shown in Figs. 7,8, 9 and 10, it is then finally finished by externally threading thesame as at 31 and by cutting away its top part at an angle to provide ahead 38 having an angular seat surface 39. The threads 31 extend onlypart way to the angular seat 39 leaving a smooth, annulargasket-receiving and supporting surface 40.

The advantages of my invention first above stated will be obvious fromthe foregoing. A simple and inexpensive plug formed of sheet metal isprovided. The plug is of a single piece construction and is light inweight, which is a material factor with respect to shipping expense.Furthermore, a plug formed in accordance with my invention is strong anddurable and capable of withstanding the usage and handling to whichplugs of this character are ordinarily subjected.

I claim: 5

l. A closure plug formed entirely from a single piece of sheet metalwhich comprises a cup-shaped body having the lower part of its outerside wall threaded, a head having an angled seat surface formed at thetop of the outer side wall of said 10 body, said head being spaced fromsaid threaded portion to provide a gasket-receiving space, the side wallof said body having diametrically-opposed, inward indentationstriangularly-shaped in cross-section providing internal lugs adapted to15 be engaged by a suitable tool to rotate the plug.

2. The method of forming a sheet metal closure plug having a cup-shapedbody which comprisesthe steps of shaping a preformed cylindrical fiatblank of sheet metal of uniform thickness into 20 the form of a cup ofsubstantially uniform diameter, striking the side wall of the cupradially inward at diametrically opposed points below the upper or freeedge of the cup and simultaneously compressing the side wall of the cupin axial di- 26 rection, thereafter additionally compressing the cupside wall in axial direction to finally compact and thicken the same andsimultaneously and finally shaping the inwardly struck portions toprovide inwardly-extending lugs triangularly 30 shaped in cross-sectionwithin the finished plug, and externally threading the outer wall of thecup.

3.- The method of forming a sheet metal closure plug which comprises thesteps of shaping a preformed, cylindrical fiat blank into the form of a35 cup of greater depth than the finished plug, striking the side wallof the cup radially inward at a plurality of points to providetriangularly-shaped lugs within the cup, compressing the cup side wallin axial direction to thicken the same and to 0 bring it to the finisheddepth of the plug, and finally externally threading the compressed sidewall.

4. The method of forming a sheet metal closure plug which comprises thesteps of shaping a pre- 45 formed, cylindrical fiat blank into the formof a cup of greater depth than the finished plug, simultaneouslycompressing the side wall of the cup in axial direction and striking theside wall inwardly at a plurality ofpoints finally cgmprgs s ggiak /mside wall to the depth of the finished plug and simultaneously andfinally shaping said inwardlystruck portions to provide lugs forinsertion and removal of the plug, and finishing the plug by externallythreading its outer side wall and shap- 55 ing its side wall above itsthreaded part to form a head spaced from said threads by a gasketreceiving space.

5. In a closure plug formed from a single piece of sheet metal, acup-shaped body having its lower so outer portion threaded, a head ofsubstantially the same diameter as said threaded portion provided at theupper end of said body and spaced head. I

6. In a closure plug formed of'a single piece of 70 sheet metal ofuniform thickness, a cup-shaped body having its side wall thickened andthe lower outer portion of said side wall threaded, a head formed on theupper part of said body within the diametrlcal limits of said threadedportion and 76 section that are formed from the material of said sidewall and which project inwardly toward each other from said side wall tobe engaged by a tool for applying the plug to or removing it from athreaded opening.

7. A closure plug formed entirely from a single piece of sheet metalwhich comprises a cupshaped body having the lower part of its outersidewall threaded, a head having a seat surface formed at the top of theouter side wall of said body, said head being spaced from said threadedportion to provide a gasket-receiving space, the side wall of said bodyhaving diametrically-op posed, inward indentations providing internallugs I adapted to be engaged by a suitable tool to rotate the plug.

8. The method of forming a sheet metal closure plug which comprises thesteps of shaping a-preformed, cylindrical flat blank into the form of acup of greater depth than the finished plug, striking the wall of thecup radially inward at a plurality of points to provide lugs within thecup, compressing the cup side wall in axial direction to thicken thesame and to bring it to the finished depth of the plug, and finallyexternally threadingthe compressed side wall.

RICHARD L. PARISH.

